If you know what node it is (sounds like you do), you can run "q occ"
daily, and see what filesystem is increasing the number of files stored and
space occupied.  Once you know the filesystem, you can approach the system
owner with a more direct question.  Can't help with the non-response part
(maybe some BOFHing is required).

Nick Cassimatis
nickpc AT us.ibm DOT com

Today is the tomorrow of yesterday.